NICKELODEON IS CELEBRATING 20 YEARS ON AIR

Nickelodeon brings its 20th-anniversary celebration to a peak with special programming today and tomorrow.

Among the presentations on the kids' network, which actually turned 20 on April 1, are a block of `Nicktoon Firsts` -- first episodes of the network's original cartoon series -- from 8 a.m. to noon today; a showcase of live-action series at 5 p.m., and a live `SNICK` (or Saturday Night Nick) presentation beginning at 8 p.m.

Tomorrow from 1 to 4 p.m., it will offer some before-they-were-stars glimpses of Nick performers, including James Van Der Beek kissing Clarissa Explains It All's Melissa Joan Hart, Alanis Morrisette getting slimed on You Can't Do That on Television and Backstreet Boy A.J. McLean on Hi Honey I'm Home.

Through it all, feel free to ask if Nickelodeon is really a good idea.

A wildly successful one, to be sure. From modest beginnings as an educational service on cable systems in Buffalo, N.Y., and Columbus, Nickelodeon now reaches 75 million homes and has its name on a magazine, toys, movies, home-video releases, touring arena shows and major production centers. It's had two spinoffs, the evening Nick at Nite lineup and the TV Land channel.

The empire is built on a simple philosophical premise: to be the network for kids, in its own description `the place where kids could be kids. . . . giving kids what they wanted, not what grown-ups thought was good for them.`

There had been some of that in Nick's early years -- the sliming of people began on You Can't Do That on Television in 1982 -- but it was in 1985, and after Nickelodeon became part of MTV Networks, that it solidified.

And admittedly it led to some inspired, goofy programming, such as successful cartoons like Rugrats, the live-action sketch comedy of All That and the game show Double Dare.

The network also had a conscience and has tried to do good work, notably in educational hit Blue's Clues and in Linda Ellerbee's Nick News telecasts.

At the same time, it has played a role in the fragmentation of the television audience, catering to young viewers instead of programming for everyone. That's reduced TV's ability to be a unifying experience, drawing everyone before the set at the same time.

Even during big events, some viewers are siphoned away to cable networks aimed specifically at kids, or women, or sports-crazed men. Faced with that sort of targeted programming, broadcast networks have focused their programming strategies on a limited portion of the audience, further reducing a family's chance to find a show everyone can enjoy together.

You can't blame that fragmentation on Nickelodeon alone, of course. The rise of cable in general has made TV look more like radio, splintering the audience along demographic lines.

But you can ask if Nickelodeon should really point with pride, in its own press materials, to its transition from `a 'green spinach,' 'good-for-you' network to a kid-focused, parent-approved entertainment powerhouse.`

Parents don't always approve of giving kids what they want. And kids like to talk about stuff that isn't appropriate. Gross jokes. R-rated movies. Snot.

So there have been times that, in its eagerness to cater to kids' wild side, Nickelodeon has gone too far. Ren & Stimpy -- anarchic, rude, ugly -- was a case in point; in fact, it became a favorite not just with kids but with teens and young adults, so much so that Nickelodeon's corporate sibling MTV ran it for a while as well.

Roundhouse, a Saturday-night variety show, was clearly aimed at older children and teens. Another critic a couple of years ago noted the contradiction in a self-described network for kids marketing big-screen movies with a PG rating, as Nickelodeon has done several times.

So viewers, especially parents, shouldn't get too rambunctious in their celebration of Nickelodeon. It's still TV, and kids' network or not, adults still have to keep an eye on what it does -- and whether it goes too far.